An exhaust gas heat exchanger (EGHX) is used to recover heat from exhaust gas of an internal combustion engine to heat engine coolant. Some systems use a passive control strategy with a thermostat moving a valve or actuator to control the exhaust gas recirculation.
In a hybrid vehicle, the exhaust gas heat exchanger may also provide for earlier engine shut down. An exhaust bypass line may be provided for the exhaust gas to flow around the heat exchanger and bypass the coolant. The exhaust gas flow is directed by an EGHX valve to flow through either the EGHX or the bypass. The EGHX valve typically does not have a position sensor. Prior art systems have used passive control over the EGHX valve such that a thermostat directly moves an actuator for the EGHX valve, which may lead to coolant boiling or a time lag in the system.